In the prior art, a large number of multivibrator circuits are known. Multivibrators are a known means for generating controlled waveforms and are generally categorized as being monostable, bistable, or astable. Of particular interest to the field of the present invention are monostable and astable multivibrators as these types of circuits are frequently used for the purpose of generating and providing clock pulses to other circuits within an overall network. The principal difference between a monostable and an astable multivibrator is that an astable multivibrator will run continuously providing a string of pulses while a monostable multivibrator provides only a single output pulse in response to a single input or trigger pulse.
The majority of the presently known multivibrators have been implemented in bipolar transistor technology. Relatively few multivibrators have been designed with field effect transistor (FET) circuits because of the soft turn-on threshold characteristics of field effect transistors. Such soft turn-on characteristics result in unpredictable and uncontrollable pulse widths and relatively slow rise and fall times.
Since field effect transistor circuit networks may require multivibrators for clock signal generation or other functions, the presently available alternatives are to either provide clock signals generated by multivibrators external to the field effect transistor chip or to provide an on-chip field effect transistor multivibrator which provides less than adequate clock pulses. For example, see U.S. Pat. No. 3,719,835 which shows a monostable pulse generating circuit implemented entirely in field effect transistors. This patented prior art circuit is believed to have the undesired soft turn-on characteristic of field effect transistors.